Domain Wall Pinning in Magnetic Logic Devices

Abstract

Magnetic logic devices have attracted significant amount of attention in recent years, thanks to their low power consumption and non-volatility. However, one important issue needs to be resolved before these devices can become reality, namely the pinning of magnetic domain walls. In this project, we investigate a method for pinning domain walls by locally modifying the saturation magnetization (Ms). Micromagnetic simulations indicated that the pinning strength of the proposed domain wall traps varies linearly with the change in Ms, thus making the pinning strength easily controllable. Furthermore, the study showed that under certain conditions, the pinning strengths of these traps are not affected by variations in trap lengths, rendering the traps tolerant to fabrication variations. Subsequent experiments successfully showed that local variations of Ms, induced by Focused Ion Beam (FIB) irradiation, can indeed achieve domain wall pinning. However, more detailed analysis was hindered by a large measurement noise.